Casting die



May 15, 1923. 1,455 248 C. M. GREY CASTING DIE Filed April 13 1917 WITNESSES: INVENTOR 67207765 ZYI Grey.

A llorneys Patented May 15, 1923.

NITED STATES CHARLES GREY, OF EAST ORANGE, JERSEY.

CASTING DIE.

Application filed April 13, 1917. Serial No. 161,743.

To all whom it may concern Be 1t known that I CHARLES M. GREY, a

citizen of the United btates, residing in East Orange, county of Essex, State of New,,Jersey, have. invented a certain new and useful Casting Die, of which the following is a specification.

his invention relates to the die casting art wherein moltenmetal is introduced into a die under pressure, the invention being directed, more particularly, to the die and, specifically, to a die for use in casting cored or tubular articles.

It has been the practice, in die casting tubular articles, to form the runner in the die in such manner that the-molten metal, in passing from the runner, enters the impression cavity of the die along the longitu inal side thereof, arid so that the metal, upon leaving the runner and entering said cavity, is introduced directly against the core, whereupon it flows around the same, filling the space intermediate the core and the walls of the die.

Considerable pressure is employed in the carrying out of this operation and the result is that the molecules surface of the core, are caused to rebound at various angles. These rebounding molecules set up a counteracting force against the incoming molecules of metal, producing a violent agitation of the metal at the inlet of the die. This agitation continues until enough metal has flowed into the die to substantially fill the impression cavity thereof, but during the time required for this, the violent agitation of the metal has caused it to entrain more or less of the residual air within the impression cavity in the die. As the most violent agitation, naturally, occurs immediately adjacent the entrance of the metal into the impression cavity, it is most common to find numerous pin holes along the line of the gate, when the same is removed from the casting, and frequently the finished article contains numerous air pockets or blow holes, which are so extensive, at times, as to form large blisters in the casting. Moreover, the counteracting forces due to the rebound of the metal, upon striking the core, naturally delay the entry of the metal into the die cavity, with obvious disadvantageous results.

Attempts have been made to overcome these difliculties by making the gate long and thin so that it extends along the side of metal, striking the of the die cavity for some little distance. This modification in the shape of the gate obviates, to some extent, the aforesaid agi tatlon, for the reason that there are fewer lines of superimposed molecules flowing through the gate. This is founded on the theory that, were it possible to have but two superimposed lines of molecules the rebounding molccules would fly clear of the incoming ones and which tends to reduce the effective flow of the entering metal, due to the rebound, could, therefore, not result. While the thin gate tends to decrease the agitation of the metal, it necessitates the provision of a long gate in order to get a gate area suflicient to fill the impression cavity quickly enough to obviate the production of flow marks, and, in no case, entirely overcomes the objection of blow or in holes in the casting.

The e ect of pin holes, blow holes, and blisters in die castings is well understood. In the production of rough casting, where parts are not to be subsequently plated,

polished, or otherwise finished, and wherev the appearance of the casting is immaterial, theenumerated die constructions work tolerably well. However, the stated defects render the proper finishing of the articles impossible. This is for the reason that pin holes, blow holes, and blisters generally occur at, or near, the surface of the casting, so that, when the casting is polished or trimmed, preparatory to the plating, or other finis ing operation, the air in the larger cavities or blisters, is expanded, by the heat of friction, and makes the defect more apparent, through bulging of the thin metal covering of the blister. Moreover, this polishing or trimming operation removes the tops of the blisters, which, with the pin and blow holes along the gate, generally results in a badly pitted casting, so that it is usually considered inadvisable to utilize a die cast part where appearance, in the finished article is essential.

he enumerated defects are not only bad, in themselves, but greatly interfere with plating of the parts, as chemicals, used in this operation, are apt to become entrained 4 within the pin and blow holes, causing discoloration of the plate, as well as the flaking thereof, after the article is finished.

With the foregoing in mind, the object of the invention is, primarily, to produce uniform tubular or cored die casting, subthe counteracting force,

(iii

stantially free from entrained gas or air, with the consequent result that the finished castings will have a smooth, unpitted and uniform surface.

Speaking generally, the invention embodies an impression cavity for die casting cored or tubular articles, the runner to which cavity is so positioned as to feed such tubular articles from their ends, instead of from their sides, as usual. Moreover, associated with the runner is a chamber for converting or translating the high velocity at which the molten metal usually flows from the melting pot, into pressure, so that the metal, in finally flowing into the impression cavity of the die, does so under a substantially uniform pressure, and is uniformly distributed throughout the entire area of saidvcavity. In this manner, churning or agitation of the metal within the die cavity, is obviated, with the result that the die castings thus produced are free from the superficial effects specified.

Features of the invention, other than those specified, will be apparent from the hereinafter detailed description taken in conjunction with the accompanying drawing.

In the accompanying drawing, I hate illustrated one practical embodiment of the invention, but the construction shown therein is to be understood as illustrative, only, and not as defining the limits of the invention.

Figure 1 is a face view of half of a die embodying the present invention.

Figure 2 is a section on line 2-2 of Figure 1, and

Figure 3 is a side elevation of one of the finished articles produced when the invention is practiced as shown in Figures 1 and 2:

For the purpose of illustration, the die in the accompanying drawing. is shown as adapted to simultaneously form two castings, and this showing is made so that the manner of gating may be understood. Moreover, for concrete illustration, the die as shown is adapted to produce the two component parts of a well known form of phonographic tone arm. as the production of such a device well illustrates the present invention, although, manifestly, the present invention is not exclusively limited to said devices.

Referring to the drawing. A and A designate the two parts of a die, which, as is well known, are formed complementary to one another. Two cavities are formed in the die, cavity C being of the form to cast the straight piece of the tone arm, and cavity C being of the form to cast the cooperating elbow portion of said tone arm. Die cavity C is to be understood as ending at the lines 0, which designate its opposite ends, whereas die cavity C terminates, at its opposite ends, at the lines designated 0. The

respective cavities C C are cored with the usual cores D D, as is common. In fact, the general form of the die, and the manner of molding or otherwise forming the cavities and subsequently coring the same, are in accordance with the general practice. However, instead of gating the metal to the cavities, as heretofore, this invention.embodies a radical difference in the formation of the channels or runners through which the molten metal flows to the respective die chambers.

Referring particularly to cavity C, it will be noted that, beyond one end of said cavity, designated by one line 0, there is positioned, in the form of the invention shown, an annular feed chamber G, which encircles core D and communicates, through a constricted passage g, with cavity C. In like manner, a feed chamber G is formed in the die, beyond one end of cavity C, and said feed chamber G is connected with its associated cavity C by a similar constricted passage 9'.

In one member of the die is formed a passage E, through which the molten metal is fed from the melting pot, or other source of supply. This passage communicates with a runner F in the die, from which runner lead branches f f, communicating with feed chambers G and G, respectively.

When'molten metal is caused to flow from the source of supply through the intake passage E, by an is introduced rom passage E directly into runner F of the die, and thence through its branches f f to the respective feed chambers G G. The metal, in flowing through passage E, the runner and its branches, generally travels under a high velocit and enters feed chambers G G at consi erable speed. However, before said metal can enter impression cavities C C, feed chambers G G must have been filled. Thus, the inrushing metal serves, first, to fill the feed chambers, and, after said chambers are filled, they form heads or pools, the following metal serving to place the contents of said feed chambers under pressure and force the metal through the constricted passages g 9', into the cavities C C, respectively.

In practice, I find it advisable to have the constricted passages g g less in area than the pools G G and also less in area than the branch runners f f. It is also preferable to have the junction of f with G, and f with 1G thin and broad inasmuch as it tends to obviate any tendency to build up pressure in the pools G G, until said pools are entirely filled under which conditions an even flow throughout the con stricted passages g 9' results. This even flow then acts as a solid body as it fills the associated impression cavity and thereby forces any ar contained in said cavity, ahead of it to the opposite end of the die suitable means, said metal chamber, where it is preferably disposed of in a manner hereinafter described. The metal flowing into each cavity is, therefore, introduced under a uniform pressure maintained in its associated chamber. and is uniformly distributed throughout the entire area of said die cavity. No agitation occurs within the die, as heretofore, and bubbles, etc., which would cause pin holes and blisters, are obviated.

In the initial inrush of metal to fill the feed chambers, the metal may strike against the core and become agitated or churned up. However, this state is only momentary, and is confined entirely to the feed chambers. As soon as said chambers become filled to form pools, such state does not obtain. After the feed chambers have become filled, the metal therein assumes a comparatively quiescent state, and the velocity of the incoming metal is converted, in said chambers, into pressure within the chambers, so that, instead of a quick or sudden inrush of metal directly into the die cavities, with consequent churning or agitation of the metal therein, said metal is fed into the cavities under, in effect, hydraulic pressure. There is no entrained gas or air, and the surface of the finished article is smooth and free from bubble holes.

\Vhen the die casting operation is completed, and the cast parts removed from the die in the usual way. that portion of the metal which solidified in the chamber and constricted passage adjacent each article, may be readily removed from the article itself, because of the thin wall formed in the constricted passage, thus leaving e. g.,

the article cast in impression cavity C inthe form shown in Figure 3 of the drawing.

In the form of the invention shown, the articles to be cast are open at both ends, so that the core members extend entirely through the die. However, it will be understood that, if one end of the art cle is to be closed, the core will be manipulated, in the usual manner, to satisfy the conditions'.

As heretofore stated, the flow of metal into the die cavity from one endthereof, forces the residual air in said cav ty to the opposite end thereof, and it is desirable, to provide means whereby said residual air may find ready exit. This is particularly true where the cavity is comparatively extensive, and while it is the practice in the art to space the mold halves about two or three thousandths of an inch apart to allow for the egress of some of this air, it is found in practice that the inrush of metal along the sides immediately seals the major part of the crack thus left, so that it is precluded from carrying out the desired function except to the most limited extent so that considerable air remains in the die and is not exhausted or expelled. Accordingly, I preferably employ means adapted to bring about the removal of substantially all of the residual air so that, at the conclusion of the flow of metal into the die, said air has been entirely scavenged from the impression cavity.

I have .found by experiment that this may be accomplished by providing, at the end of the impression cavity opposite to that whereat the intake is positioned, an outlet chamber, communicating with the die cavity through a passage, large enough to allow of free flow of air therethrough. When the metal is forced into the die it serves as a piston moving longitudinally of the die cavity and forces all of the residual air from said cavity through the passage at the other end thereof. Two such exhaust chambers H H are shown in the drawings, one of which cooperates with each of the die cavities C C, respectively. For the purpose of illustration, these exhaust chambers are shown substantially the same in form as the pool chambers G G, and communicate with the respective die cavities, through constricted passages h h, similar to the inlet passages g g, The shape and size of these parts, however, are not restricted to those shown, but may be changed as occasion may require or as it is desirable to make them.

It will, of course, be understood that the usual air exhausting apparatus may be em ployed in combination with a die, herein shown and described, and such apparatus is preferably used. It is found, in practice, however. that a perfect vacuum cannot be produced by the mechanical exhaustion of air from the die, so that the provision of the exhaust chambers H H serves the function of receiving the residual air of the die cavities which cannot practically be exhausted therefrom by the well known suction mechanism, generally employed. The practical employment of this invention for a considerable period has shown that substantially all of the residual air is actually exhausted from the die cavity by the end of the molding operation, so that pin holes, blow holes and blisters are practically obviated. Practically all of the work produced by the structure described is, in effect, perfect so far as these defects are concernechand enable die castings to be used in a much broader field, and for other purposes than were heretofore possible. This is even true, to some extent, when the exhaust chambers are not employed. and the invention is not restricted, in its broadest aspect, to the incorporation of these chambers into the die. However, their presence is preferable, particularly where comparatively extensive castings are to be made.

It will, of course, be understood that. when the exhaust chambers are employed. some metal flows beyond the impression cavisame manner 'as.

, an enlarged portion but, if such defects can be ties and lodges in the exhaust chambers, but

this superfluous metal can be readily removed from the casting, proper,

after said taken from the die in the the metal, which hardens in the pool chamber G and communicating passage g, is removed.

In the preferred form of the invention, the feed chamber and constricted passage through which it communicates with the die chamber, are positioned beyond the end of the die chamber, and the metal which solidifies in said feed chamber and passage is, at the end of the casting operation, broken off from the casting proper. I may, however, Where the construction of the article to be cast will permit, i. e., where there 18 at the end of the article, utilize such enlar ed portion of the die chamber as the fee chamber for the remaining portions of the casting. In such cases, more or less defects may occur at the enlarged portion, depending upon the relation between the outside diameter of such enlarged portion and the diameter of the core, allowed in that part of the finished article, then I may dispense with the use of any external feed chamber. In this instance, it will be manifest that that portion of the casting which was molded within said feed chamber will form a portion of the casting proper and is not adapted to be broken off, or otherwise removed, as is the case in the preferred manner of practicing the invention. y

In the specific embodiment illustrated, feed chambers G G are annular in form and extend entirely around the cores. It will be understood, however, that the invention is not restricted as to the form or size of these feed chambers, as said chambers will differ in these .respects in accordance with the different articles which it is desired to cast. The salient feature of the invention, therefore, resides in the provision of a feed chamber for feedin the whole or a portion of a die chamber, which feed chamber serves to convert or translate the high velocity of the molten metal in its passage from the source of supply into hydraulic pressure. This pressure will result in a lower velocity of feed into the impression cavity while retaining the advantage of high pressure for forcing 'the metal into the die and finally compressing the metal within the impression cavity as it cools. A further feature is that by gating, in the manner specified. minicasting has been mum rebound results thereby obviating the entraining of air by the molten metal with consequent disadvantages. Another well known feature, of course, is the means for allowing of the expelling of the air during the molding operation by the metal itself.

It will be manifest to those skilled in the art, that the particular shape, size and proportion of the impression cavities, pool chambers, exhaust chambers and the communicating passages, as well as the runners in the die, will vary in accordance with the articles to be cast, and it is therefore to be understood that the invention is not restricted to these details, but is as broadly novel as is commensuratewith the appended claims.

This invention, besides embodying the structure and formation of the die includes the process of die casting consisting in the various operations hereinbefore specified and enumerated in the claims to the method or rocess hereto ap ended.

aving thus fully tlzescribed the invention, what I claim as new, and desire to secure by Letters Patent, is:

1. A die for die casting cored articles embodying a die chamber to be filled with molten metal, a source of'supply for said molten metal, a feed chamber within the die, a duct leading from the source of supply to said feed chamber in the die, and a constricted passage from the feed chamber to the die chamber, whereby the feed chamber is filled from the source of supply and hydraulic pressure is generated in said feed chamber for the purpose of forcing the molten metal, under substantially uniform pressure, through the constricted passage into the die chamber. 4

2. A die for die casting cored articles embodying. a die chamber adapted to be filled with molten metal, a runner in the die, means for introducing molten metal into the runner, and a feed chamber communicating with the runner and with the die chamber, which feed chamber serves to convert or translate the velocity at which the metal flows into the die into pressure within the feed chamber, whereby the metal is fed from the feed chamber to the die chamber under hydraulic pressure.

3. A die for die casting cored articles embodying a die provided with an.- elongated die chamber adapted to be filled with molten metal, a core extending through said chamber, and means for introducing molten metal into the die chamber from one end thereof.

4. A- die for die casting tubular articles embodying a die chamber adapted to be filled with molten metal, a core extending through said die chamber, a feed chamber, a constricted passage leading from the feed chamber to the end of the die chamber, and a runner for introducing molten metal into the feed chamber, whereby, after the feed chamber is filled, the molten metal is fed, under hydraulic pressure, through said constricted passage into the end of the die chamber.

5. A die for die casting tubular articles embodying a cored die chamber, and means for'introducing molten metal into said die chamber from one end thereof.

6. A die for die casting tubular articlesembodyin a cored die chamber, and means for introducing molten metal, under hydraulic pressure, into said die chamber from one end thereof.-

7. A die casting die embodying a die chamber adapted to be filled with molten metal, a feed chamber within the die for said die chamber, and means for introducing molten metal into the feed chamber, whereby said feed chamber forms a pool or head from which the die chamber is fed.

8. A die casting die embodying an elongated die chamber adapted to be filled with molten metal, a feed chamber within the die for said die chamber, said feed chamber communicating with one end of the die chamber, and means for introducing molten metal into the feed chamber, whereby said feed chamber forms a pool or head from which the die chamber is fed.

9. A, die for die casting tubular articles embodying an elongated, cored die chamber, a feed chamber in the die communicating with one end of the die..chamber, and means for introducing molten metal into the feed chamber, which feed chamber serves as a pool or head from which the die chamber is fed.

10. A die for die casting cored articles embodying a cored die chamber having at one end a chamber, and a duct for introducing molten metal into said chamber and thence into the die chamber.

11. In the art of making die castings, the process which consists in incorporating a chamber in the path of the molten metal from the inlet to the die to the die chamber to be filled, which chamber serves to convert or translate the velocity of the incoming molten metal into hydraulic pressure.

12. In the art of making die castings, the process which consists in bringing molten metal, after the same has passed into a die, into a substantially quiescent state, and thereafter feeding the same into the die chamber to be filled.

13. In the art of making die castings, the method which consists in feeding a die chamber through a pool or head in the die, in which pool or head the velocity of the incoming metal is translated or converted into hydraulic pressure and the die chamber fed from said pool or head under such pressure.

14. In the art of making die castings, the process which consists in feeding a tubular die chamber from one end thereof.

15. In the art of making die castings, the process which consists in feeding a tubular die chamber from one end thereof and through a pool or head in the die, in which pool or head the incon'iing metal assumes a substantially quiescent state, and from which head said metal is fed into the die chamber.

16. In the art of making die castings, the process which consists in bringing the molten metal into a substantially quiescent state within the die, and before said metal passes into the die chamber to be filled, and there- Itfter feeding said metal into said die cham- 17. In the art of making die castings, the process which consist-s in forming a hydraulic pool within a die, and feeding the die chamber to be filled with the overflow from said pool.

18. In the art of making die castings, the process which consists in forming a pool of molten metal within a die, and feeding the (lie chamber to be filled with the overflow from said pool.

19. A die for die casting cored articles embodying a die chamber to be filled with molten metal, a source of sup ly for said molten metal, a feed chamber within the die, a duct leading from the source of supply to said feed chamber in the die, and a constricted passage from the feed chamber to the die chamber, whereby the feed chamber is filled from the source of supply and hydraulic pressure is generated in said feed chamber for the purpose of forcing the molten metal, under substantially uniform pressure, through the constricted passage into the die chamber, in combination with an exhaustchamber communicating with the die chamber at a portion of the die chamber remote from the constricted feed passage thereof, into which exhaust chamber residual air in the die chamber is forced when the metal fiows in the die chamber.

20. A die for die casting cored articles embodying adie chamber adapted to be filled with molten metal, a runner in the die, means for introducing molten metal into the runner, and a feed chamber communicating with the runner and with the die chamber, which feed chamber serves .to convert or translate the velocity, at which the metal flows into the die, into pressure within the feed chamber, whereby the metal is fed from the feed chamber to the die chamber under hydraulic pressure, in combination with an exhaust chamber communicating with the die chamber at a point remote from the inlet to said die chamber, and into which exhaust chamber the residual air of the die chamber is forced by the metal flowing into the (lie chamber.

21. A die for die casting cored articles embodying a die provided with an elongated die chamber adapted to be filled with molten metal, a core extending through said chamher, and means for introducing molten metal into the die chamber from one end thereof, in combination with an air, outlet at the opposite end of the die chamber, through which the residual air of the die is forced by the metal filling the die.

22. A die for die casting tubular articles embodying a cored die cavity, means for in, troducing molten metal into said die cavity from one end thereof, and a chamber communicating with the opposite end of the die.

cavity, into which chamber the residual air of said cavityis expelled upon the flow of metal into said cavity.

23. A die for die casting tubular articles embodying a cored die member, and means for introducing molten metal, under hydraulic pressure, into said die chamber from one end thereof, in combination with an exhaust passage leading from a. portion of the die chamber remote from the inlet of said die chamberpvhereby the flow of molten metal into the die chamber causes the residual air to be forced out of the die chamber through said exhaust passage.

24. A die casting die embodying a die chamber adapted to be filled with molten metal, a feed chamber within the die for said die chamber, and means for introducing molten metal, into the feed chamber, whereby said feed chamber forms a pool or head from which the die chamber is fed, in combination with an exhaust passage leading from a portion of the die chamber remote from the inlet of said die chamber, whereby the flow of molten metal into the die chamber causes the residual air to be forced out of the die chamber through said exhaust passage. I

25. A die for die casting cored articles embodying a cored die chamber having at one end a chamber, and a duct for introducing molten metal into said chamber and thence into the die chamber, in combination with an outlet ductcommunicating with the die chamber at a portion thereof remote from the inlet to said chamber, whereby the flow of molten metal into said chamber vforces the residual air through the outlet duct.

26. In the art of making die castings, the process which consists in incorporating a chamber in the path of the molten metal from the inlet to the die to the die chamber to be filled, which chamber serves to convert or translate the velocity of the incoming molten metal into hydraulic pressure, and utilizing the flow of metal into the die chamber to expel the residual air from said die chamber.

27. In the art of making die castings, the process which consists in bringing molten metal, after the same has passed into a die, intoa substantially quiescent state, thereafter feeding the same into the die chamber to be filled, and utilizing the flow of metal into the die chamber for expelling the residual air from said chamber.

28. In the art of making die castings, the

method which consists in feeding a die chamber through a pool or head in the die, in which pool or head the velocity of the incoming metal is translated or converted into process which consists in feeding a tubular die chamber from one end thereof, and utilizing the flow of metal into the die chamber for scavenging said chamber of residual air.

30. In the art of making die castings, the process which consists in bringing the molten metal into a substantially quiescent state within the die, and before said metal passes into the die chamber to be filled, thereafter feeding said metal into said die chamber, and utilizing the flow of metal into the die chamber for scavenging said chamber of residual air.

31. In the art of making die castings, the process which consists in forming a hydraulic pool within a die,'feeding the die chamber to be filled with the overflow from said pool, and utilizing the flow of metal into the die chamber for scavengingsaid chamber of residual air.

32. In the art of making die castings, the

process which consists in forming a pool of molten metal Within a die, feeding the die chamber to be filled with the overflow from said pool, and utilizing the fiow of metal into the die chamber for scavenging said chamber of residual air.

33. In the art of making die castings which consists in utilizing the flow of metal into the die chamber for scavenging the die chamber of residual air.

34. In the art of making die castings, the process which consists in utilizing the flow of molten metal into the impression chamber of a die for hydraulically scavenging said impression chamber of residual air.

35. In the art of making die castings, the process which consists in feeding molten metal into the impression cavity of a die from one end thereof, and utilizing the flow of metal into said cavity for hydraulically scavengin the cavity of residual air.

36. A 1e for casting articles embodying an impression'cavity, means for introducing molten metal into said cavity, and an exhaust passage leading from said cavity, whereby the flow of metal into the cavity causes the residual air therein to be expelled through said passage.

37. The method of pressure casting for forming a tubular metallic body which consists in forcing molten metal under pres sure through a feed duct in a die or mold into a terminal distributing chamber or feeding chamber at an end of and communicating with the tubular die or mold cavity within which the tubular body is formed.

38. The method of pressure casting for forming a tubular metallic body which consists in forcing molten metal under pressure through a feed duct in a die or mold into a terminal distributing chamber or feeding chamber at an end of and communicating with the tubular die or mold cavity within which the tubular body is formed, and after the casting is removed from the mold or die then severin or cutting ofi from the end of the tubular hody the boss or projection which has, been formed thereon by the surplus metal contained within said terminal feeding or distributing chamber.

39. A die or mold for pressure casting for forming a tubular metallic body, such die or mold having therein a feed duct through which the molten metal is forced under pressure, a distributing chamber or feeding chamber for receiving the molten metal from the feed duct, a narrow annular gate through which the molten metal is forced from the feeding chamber, a tubular mold cavity for the contiguous part of the mold cavity for the tubular body to be cast, so that a terminal shoulder will be formed upon the end of the tubular body adjacent to the gate, whereb after the casting is removed from the mo (1 or die the boss or projection which has been formed thereon by the surplus metal which was. contained within said terminal feeding or distributing chamber may be severed or cut off from the end of the tubular body at a point adjacent to said shoulder.

40. A die or mold for pressure casting for forming a tubular metallic body, such die or mold having therein a feed duct through which the molten metal is forced under pressure, an annular distributing chamber or feeding chamber for receiving the molten metal from the, feed duct, a narrow annular gate through which the molten metal is forced from the feeding chamber, a tubular mold cavit for forming the tubular body, into an en of which the narrow gate opens, such gate being of less capacity or area transversely of the tubular body than is either the feeding chamber or the contiguous part of the mold cavity for the tubular body, whereby an annular boss will be formed upon the end of the bod of the casting and will be joined thereto y a thin annular neck with which. the adjacent end of said tubular body forms a shoulder, and whereby after the castinghas been removed from the mold or die the annular boss or prejection which was formed by the surplus metal contained within the annular distributing chamber or feeding chamber may be severed or cut off from the end of the tubular body at the neck formed thereon.

41. A die or mold for pressure casting comprising complementary mold-forming or die members provided with recesses forming between them an interior mold space or cavity for casting a tubular body, a core extending into said mold cavity, an annular distributing chamber or feeding chamber provided for the molten metal and surrounding said core at an end of said mold cavity, an annular gate being provided for connecting said distributing chamber or feeding chamber with the adjacent end of said mold cavity for forming the tubular body, and a runner or duct for molten metal being provided communicating with said feeding or distributing chamber.

42. A die or mold for pressure casting comprising complementary mold forming or die members each provided with a recess forming between them an interior mold space or cavity for casting a tubular body, a core extending between said members into said mold cavity, a recess ineach of said members formin between said members a curved distributing chamber or feeding chamber for the molten metal conformed to said core at an end of said mold cavity from which the core enters communication between said distributing chamber and the adjacent end of said mold cavity for the tubular body being provided along the circumference of the adjacent end of said mold cavity for forming the tubular body, and a runner or duct for molten metal being pro vided communicating with said feeding or distributing chamber.

In testimony whereof I have signed my name to this specification.

CHARLES M. GREY. 

